1. Field of the invention
The invention is directed to a device for switching the operating modes of a microscope tube between the observing position, the recording position, and the simultaneous observing and recording position.
2. Description of the related art
Microscope tubes for switchable binocular observation and photographic recording or for the connection of video cameras are often built with only two possible switching positions. This is due to the required width of the tube which usually amounts to three prism widths when two switching positions are provided and would amount to about five prism widths if three adjacent switching positions were provided. Assuming a prism width of 30 mm, this means a space requirement of 150 mm in width. However, in many applications there is a need for one-hundred percent observation as well as one-hundred percent photography and also a divider ratio between both operating modes with simultaneous availability of both binocular partial beam paths.
In U.S. Pat. No. 2,910,913, a continuous beam path, a partially reflecting prism, and a fully reflecting prism are arranged adjacent to one another in a spatially very wide arrangement. This arrangement is not very advantageous either in appearance or with respect to the space requirement and material requirement. In addition, a wide tube limits the accessibility and visibility of additional operating elements located on the microscope.
EP 85317 A1 describes a slide which is switchable in three positions and pushes a prism into the beam path in each case. This likewise has a negative influence on tube width.
DE 3636616 A1 provides two prisms and a switchable mirror which must be driven in a relatively elaborate manner by separate driving means.
DE 3318011 C2 is directed to an add-on device for stereo-microscopes with elements in a plurality of planes and different elaborate guides.
DE-U1-8712342 discloses a prism carriage which is only displaceable between two positions.